PART 2: PALEONTOLOGY 

 INTRODUCTION 



In the following pages will be found descriptions of the identifiable 

 fossils obtained from the Canadian and Ordovician beds in South 

 Manchuria, together with some Ordovician fossils from central 

 China. With much more adequate stratigraphic data and with a 

 greater quantity of carefully collected material, this more intensive 

 study quite naturally finds certain previous determinations inade- 

 quate or erroneous. I had to make many changes of generic names, 

 especially for the actinoceroid cephalopods. 



The fossil descriptions are arranged in the accepted biologic order, 

 but the illustrations are in a strictly stratigraphic sequence. This 

 unorthodox arrangement is believed to be more convenient for ref- 

 erence by field workers. 



SPONGIAE 

 Genus ANTHASPIDELLA Ulrich and Everett, 1890 



ANTHASProELLA? RADIATA, new species 



Plate 30, Figures 7, 8 



Description. — The entire specimen is funnel-shaped, the stem com- 

 paratively strong, subcylindrical, and narrowed below. It is pene- 

 trated by the more or less confluent and comparatively regularly dis- 

 tributed small canals, rarely more than 0.2 mm in diameter. On the 

 top of the specimen, these small canal series generally radiate from 

 the interior margin of the cup to the outer margin of the specimen 

 and are spaced about 10 in 2 mm of the length of each transverse 

 row. A vertical section of the specimen shows that the central por- 

 tion of the stem is traversed by vertical canals opening into the base 

 of the cup. These canals continue into the walls forming the cup, 

 where the terminal parts of the canals curve gradually inward, open- 

 ing into the cup cavity, and outward where they open on the outer- 

 side. In the vertical section, ciliated chamberlike cavities seem to 

 occur here and there. The cup wall appears to consist of but one 

 layer. 



Height of specimen, 25 mm; diameter of stem, 24 mm; approxi- 

 mate diameter of the specimen at the top, 59 mm ; approximate diam- 

 eter at cup margin, 23 mm; depth of cup, about 14 mm; average 

 thickness of cup wall, 14 mm. 



Gomfarison. — This specimen may be compared with Anthaspi- 

 dellaC^.) vmgniflca Ulrich and Ev^erett from the Trenton group, 

 36 



